Lennox XP14-018-230-06 Nstallation And Service Instructions page 41

Compressor Delay (P5)
The defrost control has a field-selectable function to
reduce occasional sounds that may occur while the unit is
cycling in and out of the defrost mode.
S
Units with defrost control 100269-02: The compressor
will be cycled off for 30 seconds going in and out of the
defrost mode when the compressor delay jumper is
removed.
S
Units with defrost control 100269-04: The compressor
will be cycled off for 30 seconds going in and out of the
defrost mode when the compressor delay jumper is
installed.
NOTE — The 30‐second compressor feature is ignored
when jumpering the TEST pins.
Time Delay
The timed‐off delay is five minutes long. The delay helps to
protect the compressor from short‐cycling in case the
power to the unit is interrupted or a pressure switch opens.
The delay is bypassed by placing the timer select jumper
across the TEST pins for 0.5 seconds.
Test Mode (P1)
A TEST option is provided for troubleshooting. The TEST
mode may be started any time the unit is in the heating
mode and the defrost thermostat is closed or jumpered. If
the jumper is in the TEST position at power-up, the control
will ignore the test pins. When the jumper is placed across
the TEST pins for two seconds, the control will enter the
defrost mode. If the jumper is removed before an
additional 5-second period has elapsed (7 seconds total),
the unit will remain in defrost mode until the defrost
thermostat opens or 14 minutes have passed. If the jumper
is not removed until after the additional 5-second period
has elapsed, the defrost will terminate and the test option
will not function again until the jumper is removed and
re-applied.
Pressure Switch Circuit
The defrost control incorporates two pressure switch
circuits. The high pressure switch (S4)
factory‐connected to the defrost control's HI PS terminals
(see figure 21). The defrost control also includes a low
pressure, or loss‐of‐charge‐pressure, switch (S87).
Switches are shown in wiring diagrams in figure 23.
During a single demand cycle, the defrost control will lock
out the unit after the fifth time that the circuit is interrupted
by any pressure switch wired to the defrost control. In
addition, the diagnostic LEDs will indicate a locked‐out
pressure switch after the fifth occurrence of an open
pressure switch as listed in table 14. The unit will remain
locked out until power to the defrost control is interrupted,
then re‐established or until the jumper is applied to the
TEST pins for 0.5 seconds.
Defrost Control Diagnostic LEDs
The defrost control uses two LEDs for diagnostics. The
LEDs flash a specific sequence according to the condition.
Table 14. Defrost Control (CMC1) Diagnostic LED
(XP14-XXX-230-08 and Later)
Mode
No power to control
Normal operation / power
to control
Anti‐short cycle lockout
Low pressure switch fault OFF
Low pressure switch
lockout
High pressure switch fault Slow FLASH
High pressure switch
lockout
NOTE — The defrost control ignores input from the
low‐pressure switch terminals as follows:
S
during the TEST mode,
S
during the defrost cycle,
S
during the 90‐second start‐up period,
S
and for the first 90 seconds each time the reversing
is valve switches heat/cool modes.
Page 41
Green LED
Red LED (DS1)
(DS2)
OFF OFF
Simultaneous Slow FLASH
Alternating Slow FLASH
Slow FLASH
OFF ON
OFF
ON OFF
XP14 SERIES